An apostrophe's appropriate use

There are many English speakers who have doubts or misconceptions about where to use apostrophes (the character '). In summary, it has two uses.

1. Forming contractions

Apostrophes are used in the shortened forms of phrases that we call contractions, such as can't, don't, couldn't and would've, taking the place of the letters removed. Double contractions such as wouldn't've have two apostrophes, though it should be noted that double contractions are cumbersome and best avoided in all but casual speech.

2. Indicating possession

A noun becomes its possessive form by adding 's - or in some cases, just ' - to the end.

a. General rules:

- Add 's to singular nouns ("the man's car")

- Add ' to plural nouns ("the two girls' dolls")

- Add ' to proper nouns ending in s ("Mr. Douglass' business")

b. Counter rules:

- Add 's to plural nouns that do not end in s ("the children's teacher")

- According to some, add 's to a one-syllable proper noun ending in s ("James's house")